The PD ultrasonic array positioning method is a new method combined by ultrasonic array sensor and array signal processing technology. This paper developed a set of PD positioning system based on a circular ring ultrasonic array sensor. Firstly, we can get nine arrays and sixteen arrays circular ring ultrasonic array sensor by assembling ultrasonic array sensor element and array sensor assembly that we designed and developed, and accordingly set up a set of PD experimental positioning system. Then we carried out a large number of PD positioning experiments using the existing PD ultrasonic array positioning methods. At last, the results from some experiments show that the positioning system is effective to locate PD source and can meet project needs.